So yesterday someone I know was playing this mix and im not sure who its produced by but im in desperate search of itů first song was like a house remix of firework by katy perry. Later on, there was some krewella and feel so close to you by calvin harris was also remixed in there. It wasnt a mashup but a continuous mix of like older pop songs and dance songs- anyone have an idea?
A lot of it seemed like house music but idk

Honestly..a mix like that could have been done by anyone..any where in the world. It's not like you're looking for the title of an individual track, but rather a load ton of tracks..the names of which YOU don't even know..so how is anyone supposed to be able to pin this down for you?

Your best bet, as lolirl implied, is to go back to that person and just ask them..unless you've bullshitted them at the time, buy pretending you knew what they were playing..in which case, I'm sorry to say, you've shot yourself in the foot on this one.